What do Kristen Bell, Sophia Bush, and Elizabeth Olsen have in common (besides being ridiculously talented, gorgeous actresses)? Their commitment to being eco-friendly. In honor of Earth Day, we caught up with each of them and asked them to get honest with us about their beauty habits. Things got real. Check it out.

"I would honestly say I drink three gallons a day," she says. "I don't do as good of a job when I'm not breast-feeding, but now there is an unquenchable thirst because so much water is leaving my body at all times. I'm on a constant quest to refill my bottle around the house."

...washing her face every night.

"It's never an option not to because otherwise I'll break out in the morning," she says. "Period. That is the consequence. Also, my eyes are very sensitive to any eye makeup being on for too long. So my eyes will be sort of red and a little bit swollen if I sleep with mascara on. As a new mom, I am constantly looking for ways to cut corners without too much sacrifice. The [makeup] wipes have become especially my favorite because after a day of dealing with a toddler and a newborn, if I pass out on my bed and I'm too tired to get up, having them right there on my nightstand is a way for me to commit to taking everything off my face. I don't have to get up and do the whole rigamarole of standing at the sink and washing."

"I get very culinary with my beauty regimen," she says. "I've used coconut oil as a body moisturizer. I've done avocado, or a mixture of avocado and mayonnaise, in my hair as a conditioner. As a body scrub brown, sometimes I'll mix sugar, honey, and coconut oil. But [outside of the kitchen] I haven't experimented that much with weird ingredients, partly because I try and make a commitment to acknowledging where the ingredients are harvested from. For instance, if a super-rare berry is from the middle of the Amazon, it may not be harvested very responsibly, and maybe the Amazon needs it, and I don't need it on my skin."

...her biggest beauty guilty pleasure.

"If left alone in the bathroom for a long enough period of time, I will pick at my face. I will squeeze every blackhead that I see," she admits. "It's not a great habit, but if I'm being honest, it's something I do. You can't get around the fact that it's so rewarding. It's just not good for my skin under any circumstance, so I try desperately not to do it, but I seem to often fail."

Kristen's Earth Day Cause: Neutrogena Naturals (Bell is the brand ambassador) is partnering with the Nature Conservancy to help conserve water through the #WipeForWater campaign. The campaign is challenging consumers to wash their faces without water for one week—and instead use the new Neutrogena Naturals Purifying Makeup Remover Cleansing Towelettes (which are made from 100-percent renewable fibers). For each pledge on wipeforwater.com, Neutrogena will contribute $1 to the Nature Conservancy to support water conservation, up to $50,000.

"Every day," she says. "Going to bed takes far longer than waking up. I wake up, brush my teeth, splash cold water on my face, and then I exercise. I always try and wash my face after a workout. At night, I wash with a light scrub, put on my eye cream, and then use a heavy night cream."

"I love taking my time when I layer products," she says. "I think it's important to let each layer soak before adding the next so that eye cream, serum, and moisturizer don't become one mixed product."

...the oddest thing she has put on her face.

"When I was in middle school, I would put toothpaste on my pimples," she says. "I don't know why I thought that would dry them out."

Elizabeth's Earth Day Cause: The actress has partnered with Kiehl's to create a limited-edition, personally designed Creamy Eye Treatment With Avocado. One hundred percent of the net profits, up to $50,000, will benefit Recycle Across America. The funds will be used to create 65,000 standardized recycling labels for 650 K-12 schools in the United States to encourage and simplify recycling. For more information, visit kiehls.com/earthday.

"I've been using coconut oil as a hair mask for a long time, and it's amazing," she says. "There's not an ounce of worry that happens when I rinse it out and it goes down the drain—which will eventually become someone's drinking water. Also avocado oil is such a good makeup remover. You get it at Whole Foods...I've started keeping organic cotton balls and avocado oil with me and it's just so good for you skin. It's a good little win-win life-hack."

...skipping sunscreen.

"Yes, I have done it," she says, "and I always regret it."

...her beauty obsessions.

"I'm obsessive about my eyebrows," she says. "I literally tweeze them every day. The second a little hair starts to grow back, it's out. I do not let anyone else touch my eyebrows. Ever. I use Tweezerman tweezers religiously. And I love to do other people's eyebrows. In college it became my duty in housing—people would come into my room and I would sit in their lap with tweezers and just go to town. I love it."

Sophia's Earth Day Cause: Bush and EcoTools are sharing green living tips on social media as part of the Live Beautifully, Give Beautifully campaign. All EcoTools products are made using renewable, recycled, and cruelty-free materials. As part of the campaign, for each makeup brush sold in the new EcoTools Complexion Collection, $1 will be donated to Global Green USA, up to $100,000. Global Green USA is a national nonprofit organization and the American affiliate of Green Cross International, created to foster a global value shift toward a sustainable and secure future.